Electrical relay



May 17, 1938. B. E. OHAGAN ELECTRICAL RELAY Filed NOV. 8, 1935 0 g T r c 5 4 4 B 1 2 S T Q 41 1 J- f p w M 5 F HE Tm 3 w T 1 c b a 11 a m 5 T m D 5 Z :5; R w J c 29 f w LP9 YJ M D M 25: R L b w b 5%, 1 u m 1 w R 2 0 5: k1 r 1 u 1 W w a )1 0 1 7 I 1 5 F m M w F'IIIT A A A 5, M W A M 5 0 a Mmm a 2 B INVEN TOR B napd E. 0H0 an HIS ATTORNEY Patented May 17, 1938 UNITED- STATES PATENT OFFICE ELECTRICAL RELAY Application November 8, 1935, Serial No. 48,884

1 Claim.

My invention relates to electrical relays, and particularly to relays of the type known as decoding relays for use in apparatus for controlling wayside and cab signals by means of coded track circuit current.

One feature of my invention is the provision of a novel and improved decoding relay which has no moving parts.

Other features of my invention will become apparent as the description proceeds.

I will describe one form of relay embodyingmy invention, and will then point out the novel features thereof in the claim.

The accompanying drawing is a diagrammatic F View showing a railway signaling system including a relay embodying my invention.

Referring to the drawing, the reference characters l and I designate the track rails of a stretch of railway track over which trafiic normally moves in the direction indicated by the arrow. These track rails are divided, by means of insulated joints 2, into a plurality of similar track sections, only one of which, 34,' is shown complete in the drawing. Traflic entering each track section is controlled by a signal designated by the reference character S with a distinguishing exponent corresponding to the location. These signals may be of any suitable type but, in the form here shown, these signals are of the color light type, and each comprises a red lamp R, a yellow lamp Y, and a green lamp G, which lamps, when illuminated indicate stop, caution, and proceed, respectively.

Located at the leaving end of each track section are means for supplying to the rails of the associated section coded alternating current, the code frequency of which is controlled by traflic conditions in advance. of my present invention and in the well-known form here shown comprise a track transformer designated by the reference character T1, with a distinguishing exponent, the secondary of which is constantly connected with the rails of the assoelated section in series with the usual current limiting impedance 5, and the primary of which is connected with the terminals BX and CK of a suitable source of current, not shown in the draw ing, over the contact I 5 of a coding device CT-IBII, or the contact 16 of a coding device CT-15, according as the front contact I'I|'|, or the back contact l|-ll of a relay H which is associated with the section next in advance is closed, only the coding devices CT-i5 and CT-l80 and the relay H which is associated with the section 34 being shown in the drawing. The coding device These means form no part- CT-IBII is constantly supplied with current from a suitable source the terminals of which are indicated by the reference characters B and C, and this coding device constantly opens and closes its contact l5 at the rate of 180 times per minute. The coding device CT-TS is likewise constantly supplied with current from the terminals B and C, and constantly opens and closes its contact H5 at the rate of 75 times per minute. It will be seen, therefore, that when the relay H of a section is picked up so that its front contact l'l-l| is closed, the rails of the section next in rear will besupplied with alternating current which is periodically interrupted or coded at the rate of 180 times per minute, but that, when the relay H of a section is released, so that its back contact l l-l'l is closed, the rails of the section next in rear will then be supplied with alternating current which is periodically interrupted or coded at the rate of '75 times per minute. The I80 code is used to provide a proceed indication and the code is used to provide the caution indication,

in a manner which will be made clear as the description proceeds. Each relay H is controlled by traffic conditions in the associated section in a manner which will also be made clear as the description proceeds.

Each track section is provided at the entering end of the section with what I shall term a de coding relay of the saturation type, designated by the reference character DR, only the relay DR associated with section 3-4 being shown in the drawing. This relay embodies my present invention, and in the form here illustrated comprises a main core 6 of the three-legged shell type, and an auxiliary C-shaped core 1 which is separated from the one outside leg 6% of the core 6 by a pair of air gaps 8. The main core 6 is provided with a primary winding 9 consisting of a single coil disposed on the leg 6; with an input or saturation winding l0 consisting of two coils Ill and lo disposed on the two legs 6 and 6, respectively, and connected in series in such manner that current flowing in these two coils will cause a flux to circulate around the closed path formed by the associated legs but not in the path including the leg 6; and with a secondary or output winding ll consisting of two coils H and ll disposed on the two legs 6* and 6, respectively, and connected in series in such manner that the voltages induced in these two coils due to flux from the primary winding 9 are additive. The auxiliary core I is provided with a secondary or output winding I2 consisting as here shown of a single coil.

The primary winding 9 of relay DR. is con stantly connected with terminals BX and CK or the alternating current source, and it will be apparent that with the two coils Ill and Ill of the input winding l0 arranged in the manner just described. the flux due to the current flowing in the primary winding will normally not induce any net voltage in the winding ill since the voltages induced in the two coils of this winding will be equal and opposite. The input winding I0 is energized from the associated track section 34 through the medium of a relay transformer RT which insulates the winding It from the track rails, and a rectifier RI which converts the coded alternating current received from the rails into pulses of unidirectional current in winding ill. The parts are so proportioned that during the on period of the code. the rectified current in winding ill will saturate the portion of the main core on which the secondary winding Ii is wound, so that this portion of the core'will have a ,high reluctance for the primary flux. The primary flux will then have a path of lower reluctance through the air gaps 8 and the auxiliary core I, and the voltage induced in the secondary winding 12 will therefore be relatively high while that induced in the secondary winding II will be r lativeiy low. During the off period of the code, however, the input winding I0 receives no current, and under these conditions, the portion of the core on which the secondary winding II is wound will form a lower reluctance path for the fiux from the primary winding than the path through the air gaps 8 and the auxiliary core I, thus causing the voltage induced in the secondary winding Ii to be relatively high, and the voltage induced in the secondary winding I! to be relatively low.

In order to reduce the power which is required to saturate the relay core 6, the two legs 6 and 6 of this core may be'provided with portions 20 of reduced cross sectio" between the input or saturating winding l0 and the secondary winding H in themanner shown. With the core constructed in this manner, the current which must be supplied by the track circuit need only be large enough to saturate these portions of reduced cross section of the core, and need not be large enough to saturate the complete magnetic circuit. When the portions of reduced cross section of the core are saturated, these portions of the magnetic circuit are. in effect, two large air gaps which have a greater reluctance than the reluctance of the physical air gaps 8 between the auxiliary core and the main core. With the ordinary three-leggedtype of saturation relay, it is necessary to saturate a complete magnetic circult, which must be large in order to provide high impedance to alternating current when the core is not saturated. p

The current which is induced in the secondary winding ll of the decoding relay DR is rectified by an associated rectifier RF, and is impressed manner that this current will flow through the portion l3 from left to right, as indicated by the arrow. The current induced in the secondary winding l2 of the decoding relay DR is likewise rectified by an associated rectifier R and is impressed across another portion l3 oi. the primary winding of the associated decoding transformer DT in such manner that this current will flow through. the portion l3 from right seen, therefore, that when coded current is being supplied to the decoding relay DR, both portions l3 and l3 of the primary of the decoding transformer DT will be supplied with direct current, which current will flow through these portions in opposite directions, but that, during the on period of the code, the current which flows in the portion I3 will be considerably larger than that which flows in the portion [3* whereas, during the off" period of the code, the current which flows in the portion i3 will be considerably larger than that which flows in the portion I3". It follows, therefore, that whenever coded current is being supplied to the decoding relay, an alternating current will be induced in the decoding transformer DT in substantially the same manner as has been accomplished heretofore by a decoding relay having a moving contact, and that this alternating current will have a frequency which depends upon the code frequency.

The decoding transformer DT supplies energy to the relay H for section 3-4 through the medium of a secondary winding l4 and a rectifier R Relay H is a direct current. relay and is so designed that it will remain energized whenever transformer DT is receiving energy from either the 75 or the I code. The decoding transformer DT for section 3-4 also supplies energy to a direct current decoding relay. J which is connected with a portion of the winding of the decoding transformer through a decoding unit DU-IBO. The detaim of construction of the decoding unit DU-lflii are not shown in the drawing, but this unit usually comprises a rectifier and a reactor condenser tuning unit for tuning relay J whereby this relay will be energized when and only when the I80 code is being supplied to the decoding relay.

When relays H and J 'are both energized, a circuit is completed for lamp G of signal S which circuit passes from terminal BX of the source through front contact Iii-l8 of relay H front contact I 9-H of'relay J and the filament of lamp G to terminal CX. When thisv circuit is closed, lamp G is lighted and under these conditions signal S indicates proceed. When relay H is energized and relay J is deenergized, lamp Y of signals then becomes lighted by virtue of a circuit which passes from terminal BX through front contact Iii-l8 of relay H back contact l9---i9 of relay J and the filament of lamp Y to terminal X, and under these conditions, signal S indicates caution. When, however, relay H is deenergized, lamp R of signal S becomes lighted by virtue of a circuit which passes from terminal BX of the source through back contact |8--|8 of relay H and the filament of lamp R of signal S to terminal X. thus causing this signal to indicate stop.

The operation of the apparatus as a whole is as follows: Section 3-4 will be supplied with the i8. code or the-l5 code according as'the section next in advance is unoccupied or occupied. When section H is supplied'with I" code and no train occupies this section, all parts will occupy the positions in which they are shown in the drawing. That is to say, relays H and J will both be energized, the circuit for the proceed lamp G of signal 8 including contact lS-l l of relay H and contact l9-l8 of relay J will be closed, thus causing this lamp to be lighted so that the signal will indicate proceed, and the circuit for the primary of transformer '1? including front contact w left, as indicated by the arrow. It will I'l--i'l of relay H and contact ii of coding de- 75 vice CT-Jll will be closed. so that the section next in rear 01' section 3-4 will also be supplied wan is] code.

When section 3-4 is supplied with the II code and no trainoccupies this section, relay H will remain picked up but relay J will become released, thus causing signal S to indicate caution. The rails oi the section next in rear of section 1-4, however, will continue to be supplied with ill code in the same manner as when section 3-4 is supplied with the l" code and no train occupies this section.

When a train enters section 3-4, the train will shunt away'coded current from the coding apparatus, and relays H and J will then both become released, thus causing signal S to indicate stop, Furthermore, with relay H released, the circuit for the primary 0! transformer '1'! including back contact i'I----l l of relay H and contact it of coding device CT-fli will now be closed, thus causing the rails oi the section next in rear of section 3-4 to be supplied with the II code.

It should be particularly pointed out that while in describing a relay embodying my invention, I have shown it applied to apparatus for control ling wayside and cab signals by means of coded track circuit current because of its particular adaptability for this purpose, my invention is of general application and may be used wherever a relay which functions in the manner described is needed.

Although I have herein shown and described only one form of decoding relays embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claim without departing from the spirit and scope of my invention.

Having thus described my invention; what I claim is:

A relay oi the saturation type comprising a main three-leggedclosed core of the shell type and an auxiliary C-shaped core which is separated from one leg of said main core by an air gap, a primary winding disposed on said one leg of said main core and normally supplied with alternating current, a saturation winding comprising two coils disposed respectively on the two remaining legs oi said main core and connected in series in such manner that any voltages induced thereindue to flux from the primary winding will oppose each other, a first secondary winding comprising two coils disposed respectively on said two remaining legs of said main core and connected in series in such manner that any voltages induced therein due to flux from the primary winding will be additive, said two remaining legs at said main core being provided with portions of reduced crow section between the two coils of said saturation winding and the two coils of said first secondary winding to reduce the current which must be supplied to said saturation 

